1. Field of the Invention
This invention relates to a cooling device used in general industrial fields for cooling an object by water vaporization, a condenser and an air conditioning system using such cooling device.
2. Description of the Related Art
There has been proposed a water evaporative cooling device as disclosed in Japanese Unexamined Patent Publication No. 2001-244397. The cooling device disclosed in this publication includes a sheet-like vapor permeable member that is impermeable to water and permeable to water vapor, a supply channel for allowing water to pass by utilizing a capillary phenomenon, and an impermeable member in the form of a plate or a sheet made of a material impermeable to any fluid and having heat conductivity. The impermeable member is arranged on the side of an object to be cooled as opposed to the vapor permeable member with the water passage defined therebetween. The cooling device is constructed in such a manner that water supplied to the water passage evaporates by heat exchange with water coming from the side where the object is located and that the water vapor is discharged outside of the cooling device through the vapor permeable member.
The vapor permeable member is incorporated with a permeable membrane that has been developed and applied mostly in the fields of textile industries. Such a moisture permeable membrane is obtained by adhering a thin film formed with a multitude of micropores each having a size generally corresponding to one twenty-thousandth of water droplet or one thousand times as large as water vapor molecule onto a base cloth so as to provide the resultant permeable membrane with mechanical strength. The thus produced permeable membrane includes {circle around (1)} the one which utilizes a dimensional difference between gas molecule and liquid molecule, and {circle around (2)} the one that has acquired moisture permeability with use of such a physiochemical property that moisture is absorbed on a high-moisturized side with use of hygroscopicity inherent to a polyurethane film while water vapor is discharged on a low-moisturized side
However, in the cooling device incorporated with the aforementioned moisture permeable membrane, contact of the membrane with water for an extended period wears out the membrane, which hinders long-time use of such a membrane. For instance, a polyurethane film disclosed in the publication causes hydrolysis owing to a long-time contact with water. As a result, it is highly likely that a membrane using a polyurethane film may tear due to a worn-out state of the polyurethane film in a worse case.
It is an object of the present invention to provide a cooling device, a condenser, and an air conditioning system which are free from the problems residing in the prior art.
According to an aspect of the invention, provided is a cooling device including a water passage a part of or a whole of which is defined by a vapor permeable member permeable to water vapor and impermeable to water, and has the form of a mesh and made of a material having water repellency. Such a cooling device can be provided in a condenser, and an air conditioning system.
These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawing.